1. Field of the Invention
The invention relates to an ignition energy control method and system, and more particularly to the method and system such that high ignition energy is supplied to the spark plugs only while the engine is operating under an unstable condition.
2. Description of the Prior Art
It has well been known that a diluted fuel combustion (diluted mixture of fuel and air as used for an engine) is preferable in order to improve the fuel consumption rate. However, when a diluted fuel combustion is used, the mixture is not stably ignited, thereby resulting in an unstable engine operating condition.
To overcome this problem, there exists a high energy ignition systems have been developed. For this high energy ignition system, there have been published various systems, such as for instance, a system to combine the use of the ordinary ignition means with a plasma ignition means.
In the conventional high-energy ignition system, however, since the system is configured that high energy is supplied to the spark plugs at all times to ensure good ignition even under the worst engine operating conditions, high energy ignition is performed even under engine operating conditions where no high energy ignition is required. Accordingly, an overload is always applied to the battery, generator, etc., and additionally an excessive load is also applied to the engine itself, thus causing problems such as the worsening of the fuel consumption rate and the wear of the ignition system.